Loading and unloading of shipping vessels at onshore terminals sometimes results in contamination spilling into the water surrounding the vessel. Examples of contamination include oil, fuel, and solid matter. Floating containment booms or barriers are often deployed around the vessel as a precaution. In the event of a spill, the contaminant is held within the area enclosed by the containment boom where it may be more easily cleaned up. When the containment boom is placed too close to the vessel, however, contaminant may spill into an area outside of the area enclosed by the containment boom. For this reason, it is desirable to deploy the containment boom at some distance, commonly referred to as a standoff, away from the vessel. The standoff distance is often mandated by government regulations.
The proper standoff distance is often difficult to maintain because containment booms are prone to inward movement toward the vessel hull due to high wind, tide, current conditions, or other forces pushing on the containment boom. To obviate this problem, a plurality of relatively small, individual standoff units are sometimes floated on the water between the vessel and the containment boom for the purpose of keeping the containment boom away from the vessel hull. Each of these standoff units is typically triangular in shape and is made of aluminum or plastic tubing with foam or foam fill for buoyancy. It also has been proposed to use D-shaped fenders made of flexible foam-filled tubing as individual standoff units. However, because shipping vessels are often quite large, many such standoff units must be individually handled and deployed around the ship, which increases the time required for set-up and take-down, and in turn adds to the cost of loading and unloading operations. The cost of anchoring these multiple individual standoff units in the water also can be quite significant. In addition, since there is generally no support in the areas between the standoffs, the boom can bend inwardly toward the vessel in those areas, producing undesirable gaps in protection. Moreover, storage of these multiple units can present still further problems.
Other methods which have been devised to maintain a standoff distance rely on complex deployment mechanisms, such as cranes and the like, that are fixed to the ship to place the boom into the water and hold the boom in position. Such deployment mechanisms are often expensive to install, repair and maintain, and their use is generally limited to one ship. Also, special boom designs must often be employed with such deployment mechanisms. In addition, some booms have been provided with fender elements or support arms that inflate to keep the boom away from the vessel hull. However, inflatable fenders may not have sufficient rigidity to resist compression forces and they can complicate boom design.
What is needed is standoff system which may be deployed quickly and easily. There is also a need for a standoff system that is readily collapsible to facilitate transport, recovery, storage, set-up, and take-down. What also is needed is a standoff system that is compatible for use with containment booms that have no built-in or integrated means for maintaining the desired standoff distance from the vessel, and which minimizes bending of the boom between the points of support. There is a further need for a standoff system that is inexpensive to manufacture and repair. The present invention satisfies these and other needs.